The present invention relates generally to an improved debubbler/primer valve device, and more particularly to a solvent debubbler/primer means for use in connection with solvent components utilized in high pressure liquid chromatographic (HPLC) applications. The device provides a rapid, efficient and reliable valve structure for achieving removal of bubbles and ultimate pressurization of the system pump inlet to prime the pump, with this being accomplished in the absence of check valves or other system components which frequently require moving parts and lubricants. The apparatus of the present invention has found particular usefulness in applications which require extreme purity of the solvent component, free of bubbles, in high pressure liquid chromatographic (HPLC) applications by utilizing components which do not risk system contamination, and withstand long term exposure to the full range of solvents typically used in HPLC.
In the undertaking of various operations in the high pressure liquid chromatographic (hereinafter "HPLC") sequences, it is essential that the solvent (referred to as "mobile phase" by HPLC practitioners) employed be free of bubbles which may contribute cavitation and/or partial vaporization in the inlet of the system pump. A bubble may be defined as a ball of gas or air contained in a liquid or solid medium. The system pump may, in certain instances, be a positive displacement pump which, on the inlet stroke, reduces the pressure for the zone occupied by the incoming solvent. When the solvent contains bubbles inaccurate metering of solvent by the positive displacement pump does occur. Therefore, in the solvent delivery system, it is highly desirable to provide a control valve and means of capturing incoming bubbles entrained in the system, particularly from the inlet stream of solvent. The syringe provides a means to periodically remove captured air (in the vial) and apply pressure to facilitate priming of the system pump.
In the past, various apparatus and techniques have been employed for permitting and accomplishing these priming control operations, including the utilization of control valve systems having poppets and/or other check valves present for controlling solvent reservoir pressure. Such devices have been found to contribute to a source of gas or contamination, or to offer a significant restriction of flow to the system pump, and as such, have been found to be undesirable because they degrade the performance of the HPLC system. The apparatus of the present invention utilizes a length of thin-walled tubing fabricated from polytetrafluoroethylene thermoformed flat so that when exposed to pressure differentials wherein the external pressure exceeds the internal pressure, the reverse bias prevents flow. The length of polytetrafluoroethylene thermoformed tubing functions as a check valve in the overall operation, and prevents back-flow from the priming valve back to the solvent reservoir. This is achieved without the utilization of mechanical check valves which frequently require cleaning in order to ensure positive control (preventing back-flow) to the solvent reservoir. The present arrangement permits the controllable blocking of back-flow while providing a low flow resistance path from the supply solvent reservoir to the pump, yet prevent back-flow of solvent back into the solvent supply reservoir.